Method and apparatus for forming brake drums



Oct. 28. T924. 1,513,644

' T. A. SINDELAR METHOD AND APPARATUS FOR FORMING BRAKE DRUMS Filed July 2b, 1921 3 Sheets-'Sheetvl Invenl'ov'. THOMAb A. SINDELAQ T. A. SINDELAR METHOD AND APPARATUS FOR FORMING BRAKE DRUMS Oct. 28 A9124.v

Filed July 25, 1921 3 sheets-snee; 2

1,513,644 Ti A. lSIND-ELiAR METHOD AND APPARATUS FOR FORMING BRAKE DRUMS Filed July 25, 1921 3 Sheets-Sheet 3 l s rr f.. mm. ,m l Il im A 1 ,/uuf

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Patented ct. 28, 1924.

THOMAS n.

rarest ortica.

SINDELAR, OF CLEVELAND, OHIO, ASSIGNOR T0 THE HYDRAULIC STEEL COMPANY, 0F CLEVELAND, OHIO, A CORPORATION OE OHIO.

'METHOD AND APPARATS FOR FORMING BRAKE DRUMS. y

Application led July 25,

To all whom t may concern.'

Be it kno-wn that I, THOMAS A.. SINDELAR, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and .State of Ohio, have invented a certain new and useful Improvement in Methods and Apparatus for Forming Brake Drums, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings.

This invention relates to appara-tus for forming brake drums and it is the object of the invention to provide an apparatus adapted. to turn up a true cylindrical flange from a circular sheet metal blank, and to perforate and straighten the back of the drinn withoutdistorting said cylindrical flange.

In the drawing forming a part of this specification,

Figure l is a central vertical section through the forming dies showing the movable die in raised position and a blank in position to be acted upon.

Fig. 2 is a sectional View similar to Fig. 1 but showing the dies in interengaging position with a fully formed and perforated ldrum therein.

Fig. 3 is a view taken on line 3 3 of Fig. l looking in the direction indicated by the arrows.

Fig. 4 is a detail sectional view taken on line 4 4 of Fig. 3 looking in the direction indicated by the arrows.

Fig. 5 is a sectional view similar to Fig. 1 of a modified form. y

Figs. 6 and 7 are sectional and plan views respectively of a finished brake drum.

In the manufacture of automobile brake drums, considerable difficulty has been experienced, due to the distortion of the cylindrical flange in the back straightening and punching operations. The present invention contemplates the performance ofthe forming, punching and straightening operations in one stroke of the press, the cylindrical iiange being firmly held to shape in the dies while the back is punched and'straightened, whereby distortion thereof is positively prevented. No distorting stresses are set up in the metal, and a drum produced in which the flange is perfectly round, the back flat and the perforations perfectly centered.

The drawing press consists of a stationary supporting structure l upon which is mount- 1921. serial No. 487.567.

ed a supporting bed 2 upon the central portion of which is fixed a stationary plunger die 3 having a detachable face plate 4. Mounted in a casting 5 surrounding the die 3 is a pair of vertical guide pins 6. Surrounding and slidably mounted upon the die 3 is an annular blank supporting and stripping plate 7, which closely fits the cylindrical surface of the die and has peripheral blank positioning rib 8 upon its upper face. In stripping a finished drum from the die 4 the stripper plate is forced up by knock-out pins 9 which fit in vertical bores in the bed plate and are actuated by any suitable means (not shown) asis common in theart. The stripper plate 7 is supported by three equally spaced compression springs 10 which normally hold said plate in its uppermost position. The stripper plate 7 has also `three equally spaced limit stop bolts 11 which are adjustably connected to the stripper plate 7 by means of nuts 12 and slidably fit in bores through the casting 5 and have an enlarged head 13 fitting in enlarged bores 14 in the bed 2. Axially of the punch die 3 is a vertical bore vor passage 15 extending from the top of the die 3 down through the bed plate 2. and having a restricted punch receiving opening 16 at its upper end in the plate 4. Six equally spaced passages V17 of small diameter but otherwise similar to the central passage 15 surround said central passage. These passages permit slugs of metal removed by thepunches to fall through.

The'cooperating movable press member is attached to the plunger 19 of a hydraulic ram. The movable member comprises apair of die rings 20 and 21 removably secured to the under side of a guide plate 22 vwhich carries sleeves 23 registering with and slidable on the guide pins 6 and a rhydraulic cylinder 24 to the lower end of which the guide plate 22 is detachably connected and to the upper end of which the plunger 19 is connected. The outer retaining die ring 20 forms the tapered entrance portion while the .inner die ring 21 is substantially cylindrical to conform to theouter periphery of the finished drum. The inner ring 21 has an external diameter slightly less than the internal diam-eter of the ring 2O as shown in Fig. 1 so that the ring 21 can shift slightly to conform to the outer periphery of the drum when there are inequalities in the stock. This prevents the exertion of stresses in the forming operation tending to shift the punches out oit alinement With the apertures in the plunger die. The guide plate 22 has a recess registering with the ring 21 ot suffcient depth to accommodate a stationary punch plate 25 and a movable presser plate 2G. The punch plate 25 carries a large cene tral punch 27 and six bolt hele punches 28 equally spaced circumterentially about the p central punch 2'?. The' punch 27 is a-lined With the passage 15 and the punches 28 are alined with the )assages 17 in the plung r die 4L, and the presser plate 26 has apertures registering with each of the punches 2T and 23. f/tttached at their lower ends to the cuter portion ot presser plate 26, extending upwardly Alnough the guide plate 22 and attached to a piston 29 in the cylinder 24 are aA series et guide 30. any desired pressure will be maintained in the cylinder 2s. y InA `operationthe upper die member is raised to the position shown in Fig. 1 and circular sheet metal blank A Which just Within the peripheral rib 8 of the stripper plate 7 is laid upon the stationary plunger die 3, the stop bolts 11 (Fig. 4) being adjusted to bring the upper face of the plate 7 iush With the upper 'face ot the die. Downward movement of the plunger 19 brings the presser plate 26 into engagement with the blank A and fluid pressure ou the piston 29 maintains the presser plate 23 in firm Contact with the blank throughout the forming operation. The clamping action of the presser plate 26 prevents any shifting ot the blank during the forming operation and maintains the blank A flat against the face of the plunger die 3, positivelyy holding the central portion of the blank against distortion, While the circumterential flange is being formed. As the upper die member approaches the end of its stroke the central punch 27 and the circumferential punches 23 enter the corresponding apertures in the presser plate 26 and are forced through the blank and intoy the passages 15 and 17 through Which the punched out metal falls. in the meantime the passage of the die rings 2O and 21 over the upper end of the plunger die 3 has formed the cylindrical flange as shown in 2. At the end of the stroke the plate 26 bottoms against the base plate 25 and the full pressiA e et the ram is exerted uponrthe brake drum back to positively straighten out any deformation resulting from the flange form-ing operation.

Upon the return inoveinentl of the"l upper die member the presser plate 26 holds the iinished drum upon the plunger die 3 with considerable pressure until after they die rings 20 and 21 are lifted clear, stripping the drum 'from the ring 2O and at the same time preventing distortion of the back of the drum by pressing it against the flat face of the plunger die 3. As the stripper plate 7 is lifted bythe springs 10 it strips the finished drum- B from the plunger die 3, whereupon the finished drum may be removed, another blank inserted and the above described operation repeated.

ln Fig. 5 is shotvn a modification suitable ter lighter Work. In Fig. 4- the stationary die and support is exactly the same as in Fiss. 1 and 2 and the same numerals have been applied to the various parts thereof. The movable die member comprises a die i 31 having a beveled outer surface' and a clamping ring 32 having a correspondingly beveled inner surface fitting over the beveled ring 31 and a circumferential upwardly extending; alienino flano'e 33 fittinpE over a t: t3 b o shoulder 34 on the guide plate 315 and held in place by bolts 36. The presser plate and guide rods therefor as Well as the bed plate and punches are the same as corresponding parts in Figs. 1 and 2 and have the same reference numerals'. The fluid cylinder. hou'f'evern is replaced With a spring chamber 37 provided with a guide sleeve 38` Ainterposed bet-Ween the upper end of the chamber 37 and a plate 39 carried by the upper ends of the guide rods 30 is a compression spring 40. Extending upwardly from the plate' 39 is a guide pin 41 engaging the guide sleeve 38.

'lhe operation of the' modification shown in Fig. 5 is substantially the same as described in connection with Figs. 1 to 4.

Having described my invention, What I claim is:

combined forming andpunch-ing press comprising a socket die having a fixed bed plate, a central punch and a set of auxiliary punches surrounding the same, carried by said plate, a presser plate slidably mounted in saiddie and having apertures in alignment with said punches, guide rods secured to said presser plate and eX- tend-ing through said bed plate, and a piston connected to said guide rods.-

ln testimony whereof, l hereunto aflix my sigiiature. s m

THOMAS fr. SNDELAR. 

